Camera-mounting.



N. PEDERSEN.

CAMERA MOUNTING.

APPLICATION' FILED MAY 6,1916.

1,221,902. Patented Apr. 10,1917.

TIL B- a Z I awuewtoz M fimu UNITED STATES PATENT OFFICE.

NIELS PEDERSEN, OF PHILADELPHIA, PENNSYLVANIA, ASSIGN OR TO ARTHURBROOK, JR., OF PHILADELPHIA, PENNSYLVANIA.

CAMERA-MOUNTING.

Specification of Letters Patent.

Patented Apr. 10, 1917.

Application filed May 6, 19 16. SerialNo. 95,891.

To all wiwm it may concern:

Be it known that I, NIELS PEDERSEN, a citizen of the United States ofAmerica, and a resident of the city and county of Philadelphia, in theState of Pennsylvania, have invented a certain new and usefulImprovement in Camera-Mountings, of which the following is a true andexact description, reference being had to the accompanying drawings,which form a part thereof.

My present invention relates to camera designed for use upon aeroplanes,balloons, or other moving supports, and the object of my invention is toprovide simple and effective means for connecting a camera to itssupport so that what may be called the external optical axis of thecamera may be maintained in substantial parallelism with itself,notwithstanding movements of the support tending to disturb suchparallelism.

My invention is especially devised, and-is particularlyadapted for usein mounting a camera on an aeroplane for map making and militaryreconnaissance purposes. With a camera mounted on an aeroplane and usedfor the purposes specified, it is highly desirable, and in generalessential, if the photographs taken are to be sealed for map making orrange finding or other accurate distance determinations, that the planeof the film portion or plate undergoing expo sure shall be in opticalparallelism with the plane of the horizon, or in other words, that theexternal optical axis of the camera shall be maintained vertical. As iswell known, however, an aeroplane in use is practically nevercontinuously maintained on what may be called an even keel, but on thecontrary is constantly pitching or tipping. In consequence, a camerarigidly mounted on the aeroplane fuselage will not give pictures fromwhich distances can be sealed with exactness.

To support a camera on an aeroplane in accordance with the presentinvention, I connect the camera to the aeroplane fuselage by a cardesiancoupling or like universal,

mounting with the center of gravity of the camera below the center ofsupport of the camera. A camera thus mounted becomes, in effect, a shortpendulum having a definite natural frequency of vibration, and eachmovement of the aeroplane away from or .it, reference should be hadtoward the position of even keel tends to give the camera a pendulumoscillation about its center of support. The natural frequency ofpendulum oscillation of the camera is much higher, however, than thefrequency of the ordinary pitching and laterally swaying movements ofthe aeroplane, and in carrying out my invention I take advantage of thisdifference in frequency of movement by interposing between the cameraand the aeroplane frame, means adapted to yield readily to permit thecamera to adjust itself, plumb bob fashion, as the aeroplane tilts orpitches, but operative to substantially damp out the more rapid pendulumoscillations of the camera which each tilting or pitching movement ofthe aeroplane tends to set up.

The various features of novelty which characterize my invention'arepointed out with particularity in the claims annexed to and forming apart of this specification. For a better understanding of the invention,however, and the advantages possessed by to the accompanymgdrawings anddescriptive matter in which I have illustrated and described a preferredembodiment of my invention.

Of the drawings:

Figure 1 is a side elevation of a camera mounted on an aeroplane inaccordance with the present invention, a portion of the aeroplanefuselage being shown in section;

Fig. 2 is a plan view of the structure shown in Fig. 1; and

Fig. 3 is an enlarged sectional elevation of one of the yieldabledamping devices employed.

In the particular construction shown in the drawings, A represents aportion of the frame work or fuselage of the aeroplane, and

' B brackets attached to the frame work A other at right angles and atan appreciable distance above the center of gravity D of the camera andthe parts are so arranged that the camera tends to assume aposition inwhich the external optical axis D of the camera is vertical and theplane of the plate .or film portion being exposed is in opticalparallelism with the plane of the horizon.

' By the term external optical axis, of the 4 and means tor yieldabledamping device E which, as shown,-

comprises a cylinder, a piston E working therein, a piston rod Estuffing box 115* at one end of the cylinder permitting a restrictedcommunication between the opposite ends of the cylinder. As shown, thelast mentioned means comprises an external tubular by-pass pipe E and anadjustable throttle valve or cock Elin the by-pass pipe. The cylindergimbal trame G.

is shown as provided vwith an apertured ear E at one end which isjournaled on a stud B carried by one of the brackets B, and the outerend of the rod E is formed with an eye 1E journaled on a stud C securedto the The camera frame D is connected to gimbal trame C by a device EAwhich may be, and is shown as being, a duplicate of the device Theapertured ear E or" the device EA is pivotally connected to the stud Dof the camera D, and the ear E at the outer end of the piston rod E ispivotally I connected to the stud C carried by the gimbal frame G. Thecylinders ot the devices E and EA. are filled with a suitable fluidwhich may advantageously be oil.

With the construction described, the device li acts to regulate themovement of the gimbal "frame C and parts supported by the latter aboutthe axis of the trunnion C with respect to the aeroplane frame work.Similarly, the device EA regulates the movement oil the camera relativeto the gimbal frame about the axis of the trunnion T). ln the practicaluse of the invention the parts are so proportioned, and the flowrestricting capacity of each pass E is so adjusted by the setting ofthecorresponding valve E that the devices E and EA will practicallyobliterate all oscillatory movements oif the camera l) about its centerof support which are of the relatively high frequency of the naturalpendulum period of vibration of the camera D, while at the same timethey will yield to permit the camera to maintain its passing through athe naaneoa 1 center of gravity D below the center of support of thecamera as the aeroplane pitches and sways in normal use.

While in accordance with the provisions of the statutes l haveillustrated and described the best form of my inventionnow known to me,it will be apparent to those skilled in the art that changes can be madein the form of my invention without departing from its spirit, and thatsome features of my invention can be used withouta corresponding use ofother features of the invention.

Having now described my invention, what ll claim as new and desire tosecure by Letters Patent, is

l. The combination with a movable support, of a camera connected theretoby a suspension permitting a universal gravity adjustment oi the camerarelative to said support as the latter moves relative to a vertical linethrough the center of suspension, and means acting between the cameraand support and adapted to damp out pendulum like oscillations of thecamera while yielding to permit the camera to adjust itself to slowermovements of said support relative to said vertical line.

2. The combination with a movable support, of a camera connected theretoby a suspension permitting a universal gravity adjustment of the camerarelative to said support as the latter moves relative to a vertical linethrough the center of suspension, and means acting between the cameraand support and adapted to damp out pendulum like oscillations of thecamera while yielding I to permit the camera to adjust itself to slowermovements at said support relative to said vertical line, said meansincluding provisions for adjusting its motion retarding efiect.

3. in combination, a camera and a mounting therefor comprising a gimbalframe to which the camera is pivotally connected, supports to which saidgimbal frame is pivotally connected to turn about an axis at rightangles to the axis of the pivotal connection between the camera andtramewa yielding damping device connecting said support and gimbal frameand a yielding lib lid

means providing a restricted communication adapted to damp out pendulumoscillations between the opposite ends of the cylinder. of the cameraWhile yielding to permit the 5. The combination with the frame of ancamera to adjust itself to movements of the 10 aeroplane of a cameraconnected thereto by aeroplane toward and away from a position 5 asuspension permitting a uniform gravity of even keel.

adjustment of the camera, and means acting between the camera andaeroplane frame and NIELS PEDERSEN.

